System for roasting ores



March 18, 1941. BULLARD 2,235,311

N SYSTEM FOR ROASTING ORES Filed April 8, 1940 v 3 Sheets-Sheet l 3 E- ][aro2d zuzzari'j f I attorney March 18, 1941.

H. BULLARD 2,235,311

SYSTEM FOR IROASTING ORES Filed April 8, 1940 3.Sheets-Sheet 2 2O 3 3110mm 7 JzaroZd Ballard,

(Ittorneg 18,1941. I BULLARD 2,235,311

- SYSTEM FOR ROASTING ORES Filed April 8, 1940 3 Sheets-Sheet '3 B "Jmmza .BzzZZar'zZ,

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Patented Mar. 18, 1941 UNITED STATES PATENT OFFICE" 1 2,235,311 v I SYSTEM FOR ROASTING onns Harold Bullard, Independence, Mo. Application April 8, 1940, Serial No; 328,495 1' Claim. (01. 263-25) My invention relates to a system for drying and roasting various materials such, for instance as oil bearing and gold bearing shales, complex goldsilver-lead-antimonical-telluride ores, as well as I the more simple gold-silver ores after they have been dry crushed preferably to pulp that will pass through screens varying from sixty to eighty,

mesh.

In carrying out the invention, I provide a structure having one or more series ofretorts alternately arranged with a series ofv hot air flues. In each series the retorts and the flues are placed one above the other and the lower flue communicates with a combustion chamber from which hot air pursues a tortuous course through the flues to a stack. The pulp is fed into the upper retort and moved by conveyors through the respective retorts and finally discharged'from the lower portion of the structure. The'operation is continuous and since the pulp is not exposed condition, so that itcan be swept, out of the respective retorts with the oxygen. Removal of the sulphur bond disassociates the various elements formerly combined with the ores and thus leaves the latter in a free-milling condition so that the values can be readily recovered. In order that the invention may be fully understood, reference will now be had to the accompanying drawings, in which- Fig. 1 is a broken vertical longitudinai'section Y of the structure for carrying out the invention.

Fig. 2 is an enlarged vertical cross section on line 2-2 of Fig. 1

Fig. 3 is a broken horizontal of Fig. 1. Q

Fig. 4 shows the gear system for operating a plurality of conveyors which move the pulp through the retorts.

Fig. 5 is a vertical longitudinal section of a condenser.

Referring in detail to the different parts, 2

section on line 3 designates a structure preferably of brick, having a concrete foundation 3 and comprising side walls 4, front and rear .walls 6 and I, respectively, and a roof- 8.

As shown more clearly by Fig. 2 thestructure .is divided into a plurality of vertical compartments Ill arranged side by side and divided by vertical partition walls '2 extending from the foundation 3-to the roof 8. Angle irons l4, l6

and I8, and tie rods and 2| are employed to reinforce the structure 2 and in order to conserve fuel the walls and roof of the structure are enclosed in an insulation jacket 22 of asbestos, or I other suitable material, protected with an outer covering of metal plates 24. v

The compartments III are independent of each other and each compartment is provided at its lower portion with a combustion chamber 26 in which any suitable fuel may be burned. In the present instance I have shown each combustion a suitable source of supply, not shown, through a valve controlled feed pipe 30 and provided with a down-turned nozzle 32 terminating in front of an air nozzle 34 through'whichan air'blast is discharged that commingles with and divides the fuel oil into a fine spray to promote combustion.

The air nozzle 34 is connected to a pipe 36 leading from a blower, not shown.

Each compartment III has a series of horizontal flues 38, four being shown in the present instance, but this number may be increased or decreased according to the capacity desired. As shown by Figs. 1 and 2 the flues 38 are spaced one above the other, the lower one of which communicates at its inlet end with the outlet end of the combustion chamber 26 through a vertical flue 40 and at its discharge end with a vertical flue 42. The remaining flues 38 also communicate at their ends with the vertical flues 40 and chamber equipped with an oil burner 28 fed'from 42, the former of which has transverse bailies .torts, hereinafter described, and the front and rear walls, respectively, of the structure. The upper section of the vertical flue 40' communicates with a vertical pipe 50 having a controlling damper '52. All of the pipes 50 communicate at their upper ends with the breeching 54 of a stack 58 which carries off the products of combustion from the structure 2.

From the foregoing it will be understood that the products of combustion pursue a tortuous course from the combustion chamber 28 to the stack 58 thereby insuring economy in the use of fuel. If desired a'blower, not shown, may be connected to the stack 58 to provide a forced draft for accelerating the passage of the products of combustion through the flues.

Each compartment I8 is equipped with a series of horizontal retorts 58 arranged alternately with the fines 38 from which they are separated by horizontal partitions 88 and 82 made in sections having loosely connected overlapping joints 84 and 88, respectively, to allow for expansion and contraction. The partitions 68 and 62 rest on supports 68 and I8, respectively, a number of which are carried by the side walls 4 of the structure while the remainder are carried by the partition walls I2 asshown by Fig. 2. The partitions 88 consist preferably of flat cast iron plates.

The partitions 62 also preferably consist of cast iron and are of segmental cross section to conform to the peripheries of rotary conveyers hereinafter described.

The uppermost retort communicates at its receiving end with a hopper II through a chute I2 and at its discharge end with the receiving end of the upper intermediate retort through a chute I3. The lower intermediate retort communicates at its receiving end with the discharge end of the upper intermediate retort through a chute I4, and the lowermost retort communicates at its receiving end with the discharge end of the lower intermediate retort through a chute I8 and at its veyer 88 comprising a shaft 92 and helicoidal .paddles 84 and 95.

The shafts 82 are journaled in bearings 88 and 88, the former of which are secured to the exterior of the front wall 8 of the structure, while the latter are supported at the rear of the structure on cross beams I00 secured to standards I82. A train of intermeshing gear wheels I84 is provided for driving the conu veyers 88 in each compartment I8 and each train 0 II2 to an electric or other suitable motor II4.

By driving the conveyers as stated the upper conveyer and the lower intermediate conveyer will rotate in a reverse direction to the other two conveyers, so that the materials will be advanced .5 from the receiving end of each retort to its discharge end.

' The paddles 94 are set at an angle to advance the material while the paddles 95 are set at an angle to retract the material, but as the latter I0 paddles are less in number than the former the material will be advanced from. one retort to another. By arranging the paddles as stated the materials are agitated to a greater extent and separation of their constituents from each other n is thereby expedited.

when gold bearing ores with a sulphur bond are being treated, the sulphur is reduced from a hard crystallized state to a soft flocculent condition by the hot air circulating through the flues 38 assisted with oxygen drawn into the retorts 58 with 5 the outer atmosphere through pipes II8 controlled with valves III and extending through the rear wall I of the structure. The vapor, sulphur and other soluble sulphates when separated from the ores are swept from the retorts with the oxygen and deposited in a leaching tank II8 by means of a vacuum created with suitable means such as a suction fan I28 having its suction inlet connected to the respective retorts 58 through a condenser I22, manifold I24, and branch pipes I26 and I28, which latter extend through the front wall 6 of the structure and communicate with the respective retorts 58. As the vapor and sulphate laden air enters the condenser I22 it is sprayed with water discharged from a spray nozzle I38, to precipitate the sulphates into the leaching tank II8 through a discharge pipe I34.

'A bame I32 in the condenser I22 directs the sulphates to the discharge pipe I34.

necting a number to respective pyrometers, not shown, for indicating and recording the temperatures. In the present instance I have shown for that purpose a plurality of tubes I 36 extending transversely through the side walls 4 and communicating at their inner ends with the-retorts in the two side compartments III, the outer ends of said tubes being adapted for connection to the respective pyrometers, or other suitable indicating and recording means.

Briefly stated, the ore or shale to be treated, having been previously dry ground to the desired ,size, is fed to the uppermost retort 58 through the hopper II and (chute I2 and on being conveyed through the retorts is converted into a freemilling condition and then discharged from the structure 2 by means ofthe spiral conveyer 84.

As the pulp passes through the series of retorts 58 it is thoroughly stirred and agitated witlrthe paddles 84 and 85, so that all of the particles will be uniformly exposed to the heat thrown oil by the products of combustion passing through the flues 38, 48 and 42 from the combustionchamber. 28 to the stack 56. I have found that the pulp can be converted to a frangible, brittle condition by action of the paddles and starting with va temperature of approximately 550 degrees C. in

the lowermost retort 58, which is reduced to approximately 250 degrees C. by the time the products of combustion reach the uppermost retort, the latter temperature being sufllcient to preheat and dry the pulp.

- The foregoing'temperatures, together with oxygen drawn in from the outer atmosphere, liberate the chemical constituents such, for instance, as sulphur and arsenic which are converted into a flocculent condition and drawn oil to the condenser I22 by the suction of the suction fan I28 to be discharged into the leaching tank I I8. The

temperature may be regulated as desired with the valve controlled burner 28, the valve controlled air. blast, the valve controlled pipes III and the dampers 52.

From'the foregoing it will be understood that I have provided an apparatus which is well adapted for the purpose intended, and while I have shown and described a. preferred embodiment of the invention I reserve all rights to such other forms and modifications thereof as properly fall 75 within the spirit and scope of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

A system of the character described comprising a structure, a series of horizontal flues arranged one above another in said structure, a

combustion chamber communicating with the lowermost flue, means connecting the outlet end of one flue with the inlet end of the flue above, a series of retorts arranged alternately with said flues, means for supplying the uppermost retort with material to be treated, means connecting inclined in a reverse direction to retard the move- 10 ment of the materiah HAR OLD BULLARD. 

